Liquid cooled baffles between mixing and combustion chambers



Dec. 5, 1950 R. H. GODDARD LIQUID COOLED BAFFLES BETWEEN IIXING ANDcouausnon CHAMBERS Filed Nov. 30, 1946 '61.. away v yaw em. 7

Patented Dec, 5, 1950 LIQUID COOLED BAFFLES BETWEEN MIX- ING ANDCOMBUSTION CHAMBERS Robert H. Goddard, deceased, late of Annapolis,

Md., by Esther O. Goddard, executrix, Worcester, Mass., assignor ofone-half to The Daniel and Florence Guggenheim Foundation, New York, .N.Y., a corporation of New York Application November 30, 1946, Serial No.713,311

2 Claims. 1

This invention relates to combustion chambers as used in rockets androcket craft, and relates more particularly to devices for feedingliquid fuel and a liquid oxidizer thereto.

It is the general object of the invention to provide feeding devices sodesigned and constructed that the flow of combustion liquids and gaseswill be at all times in a rearward direction and toward the dischargenozzle and that conflicting paths of flow will be avoided.

A further object is to provide a liquid-cooled baflle structure tointercept drops of liquid fuel or liquid oxidizer which may have passedthrough and beyond the focal mixing area.

The invention further relates to arrangements and combinations of partswhich will be hereinafter described and more particularly pointed out inthe appended claims.

Preferred forms of the invention are shown in the drawing, in which Fig.1 is a partial sectional side elevation of a combustion chamber havingthe improved feeding devices incorporated therein;

Fig. 2 is a transverse sectional elevation, taken along the line 2-2 inFig. 1;

Fig. 3 is a side elevation of a bafile plate, looking in the directionof the arrow 3 in Fig. 1;

Fig. 4 is a side elevation of a modified baflie plate construction;

Fig. 5 is a sectional view of a pair of baflle plates as taken along theline 5-5 in Fig. 4; and

Fig. 6 is a view similar to Fig. 5 but showing a further modification.

Referring to Figs. 1, 2 and 3, portions of a combustion chamber C areshown, to the left-hand end of which is attached a discharge nozzle (notshown). The general shape of the chamber may be similar to thecombustion chamber shown in the prior patent to Robert H. Goddard,#2;183,313.

The combustion chamber C is provided with an extension constituting amixing chamber C, and both chambers C and C are surrounded by a jacketcasing In which provides a jacket space l2 to which a liquid fuel, asgasoline, is fed under pressure. This fuel acts as a coolant for thethin walls of the combustion chamber, and the temperature of the liquidfuel is thereby substantially raised before delivery to the mixingchamber C.

At its closed end, the mixing chamber C is provided with concentricannular partitions l5, I6 and II which define an axial recess and anannular recess 2|, both communicating with the jacket space I! andreceiving liquid fuel therefrom. The partitions l4 and It also define anannular passage 24, and the partition ll coacts with the casing of thechamber C to define an outer annular passage 25. The passages 24 and 25receive a liquid oxidizer from feed pipes and 3|.

The front ends of the recesses 20 and 2| and the annular passages 24 and25 are closed by annular conical plates 33 having spray openings 34 forfuel and 35 for oxidizer. These spray openings are angularly disposed insuch manner that the injected sprays of liquid fuel and oxidizerintersect in annular focal areas near the closed end of the mixingchamber 0'.

Baiiie plates and 4| are mounted between the combustion chamber C andthe mixing chamber C. These baille plates are of hollow construction andreceive a liquid oxidizer under pressure through feed pipes 42 and 43.After passing through the bathe plates, the liquid oxidizer is deliveredinto the feed pipes 30 and 3| previously described and is thus conveyedto the annular passages 24 and 25, from which it is sprayed into themixing chamber C.

The baffle plates 40 and 4| are provided with numerous cross passages 45and 45 respectively. It will be noted that the passages 45 and 46 areplaced out of alignment with each other to prevent unobstructedstraight-line flow from the mixing chamber 0' to the combustion chamberC.

The operation of the described construction is as follows: Liquid fuel,as gasoline, is fed under pressure through the annular-jacket space l2and the recesses 20 and 2| to the spray openings 34, and a liquidoxidizer under pressure is fed through the hollow baflie plates 40 and4| and the pipes 30 and 3| to the annular passages 24 and 25, from whichit is sprayed through. the spray openings 35.

The sprays of fuel and oxidizer mix and are intermingled in concentricannular focal areas, from which the combustible mixture then travels tothe combustion chamber C and toward the discharge nozzle (not shown).

Any drops of either of the liquids which are not intermingled andvaporized before leaving the mixing chamber C will impinge on the baffleplates 40 and 4| and will form superposed films of the two liquids whichwill thus be effectively intermingled. Straight-line passage of thedrops from the mixing chamber C to the combustion chamber C isobstructed by the staggered arrangement of the openings 45 and 46 in theassociated baffle plates.

In Figs. 4 and 5 a modified construction is shown in which the baneplates 40 and 4| are re- 3 placed by grids 50 and 5!, each comprisingheaders 52 and 53 connected by a plurality of cross tubes 54 and 55. Itwill be noted from Fig. 5 that the tubes 54 and 55 are staggeredsimilarly to the openings 45 and 46 in the baflie plates 40 and 4|. Thisgrid construction is desirable where extremely high temperatures areencountered at the entrance of the combustion chamher.

In Fig. 6, a further modification is shown, in which grids 60 and SIcomprise headers 52 and 63 connected by L-shaped cross tubes 54 and 55,which tubes are staggered as in the form previously described. The tubespresent streamlined convex surfaces to the combustion mixture, whiletheir recessed opposite sides facilitate the formation of vortices whichincrease the eflectiveness of the mixing.

In all three described forms, the baflle plates or grids areliquid-cooled and they effectively prevent passage of unmingled drops ofliquid from the mixing chamber C to the combustion cham-- ber C.

It will also be noted that the outer row of spray openings 35 from theoxidizer recess 25 is directed away from the wall of the mixing chamberC, whilethe outer row of spray openings 34 from the gasoline recess 2|is directed toward the wall of the chamber. Any drops of fuel which maypass through the outer row of fuel spray openings 34 will engage thewall of the mixing chamber C and form a protective liquid film thereonbut drops of oxidizer will be directed away from the wall.

Any usual device, such as a sparkplug, may be provided for igniting theintermingled combustibles in the mixing chamber C.

Having been thus described, the invention is not to be limited to thedetails herein disclosed, otherwise than as set forth in the claims, butwhat is claimed is:

1. In a combustion apparatus, a casing enclosing a combustion chamberand having an extension enclosing a mixing chamber having a closed end,means to feed liquid fuel under pressure and a liquid oxidizer underpressure to said mixing chamber, and hollow liquid-cooled baflie devicespositioned between the mixing chamber and the combustion chamber tointercept drops of liquid fuel and liquid oxidizer, each baflie devicehaving a plurality of openings therethrough for passage of combustiongases and mixed combustion vapors and the openings in adjacent parallelbaiile devices being staggered and being out of alignment with respectto the path of flow of said gases and vapors.

2. In a combustion apparatus, a casing enclosing a combustion chamberand having an extension enclosing a mixing chamber having a closed end,means to feed liquid fuel under pressure and a liquid oxidizer underpressure to said mixing chamber, and hollow baflie devices positionedbetween the mixing chamber and the combustion chamber to intercept.drops of liquid fuel and liquid oxidizer, each baflie device comprisinga grid having headers connected by a plu rality of liquid-cooled tubesof L-shaped cross section, and with the convex surface of each tubedirected toward the approaching gases.

ESTHER C. GODDARD, Ezecutria: of the Last Will and Testament of Robert HGoddard, Deceased.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 985,793 Fabel Mar. 7, 19111,879,186 Goddard Sept. 27, 1932 2,107,365 Bray Feb. 8, 1938 2,168,313Bichowsky Aug. 8, 1939 2,224,472 Chandler Dec. 10, 1940 2,332,866 MullerOct. 26, 1943 2,396,567 Goddard Mar. 12, 1946 2,405,465 Summerfield Aug.6, 1946 2,417,835 Moore Mar. 25,1947

FOREIGN PATENTS Number Country Date 378,868 France Aug. 24, 1907

